Tweed Champ (5F1) in Europe?

[tunghaichuan***]

And now they got me a bit confused again. In this picture:



The blue wire coming from the output transformer connects to the power tube socket, and the red to the eyelet board. But in the layout they printed out and sent with the kit, it says that the red goes to the tube socket and the blue to the eyelet board. This is probably a mistake, since A. the pictures are somewhat proof of a working amp, and B. I've looked up several other layouts on the Internet for a 5F1 and they all said that the blue wire goes to the tube socket and the red to the board. I've sent an email to TAD trying to make sure before I melt solder there - they'll likely reply on Monday.

The other wires from the output transformer I've connected thus (as per their layout): black to ground, green to tip (black to ground seems to be a common theme with the speaker wires too).

The blue and red wires are the 6v6 plate/anode and B+ connection.

Since you have negative feedback in this amp, it matters which color wire goes where. Technically speaking hooking up the wires one way will put the primary of the output transformer in phase with the secondary. If you hook up the red and blue wires out of phase, you will have *positive* feedback injected into the amp and it will squeal as it is turned up.

So you have two choices if you wire it incorrectly: 1. switch the primary wires (blue & red) or switch the secondary wires (don't know what color you have but the US standard is black and green.) It might be easier to switch the output (secondary wires) since they are on the jack.

This was one of the first things I learned when I built my first 5F1 about 15 years ago. The output transformer was wound so that the blue was B+ and red was the plate connection. I hooked them up in reverse order, normally the standard: red as B+ and blue as plate/anode. Squeal city. At the time it was easier for me to switch the secondary/output wires, so that green was grounded and the black wire when to the hot/tip of the output jack.

If you want to be sure, email TAD and ask them what the correct color coding is.

[red]

So you have two choices if you wire it incorrectly: 1. switch the primary wires (blue & red) or switch the secondary wires (don't know what color you have but the US standard is black and green.) It might be easier to switch the output (secondary wires) since they are on the jack.

Yes, the secondary wires are green and black. I've mentioned them in my previous post (wired: green to speaker jack tip, black to ground), but I've obviously got a lot more to learn (about tube amp terminology and technology) and English is not my first language, so I guess sometimes I'm not as clear as I could be - sorry.

If you want to be sure, email TAD and ask them what the correct color coding is.

I did already email TAD, but they won't answer until Monday probably. But you've made the correspondence between the primary and secondary wires pretty clear, so if I had to get it done quickly it wouldn't be much of a gamble. As it stands, I have to wait anyway for a new batch of resistors I've ordered to replace the ones in the kit that changed resistivity more than what the tolerance band spec'd - so hurying to solder the output transformer wires won't make much of a difference with regard to the power-on day. I'm just trying to ask questions and learn as much as possible.

Thank you, I really appreciate your help! If you ever write a book about tube amps, autograph the first copy for me and let me know where to send the money.

[red]

This was one of the first things I learned when I built my first 5F1 about 15 years ago. The output transformer was wound so that the blue was B+ and red was the plate connection. I hooked them up in reverse order, normally the standard: red as B+ and blue as plate/anode. Squeal city.

Looks like that would have been my fate as well, had I decided not to email TAD and be too smart for my own good about it. They've answered my email, and apparently the pictures on their website have been taken a long time ago when they were shipping the kits with a different output transformer. So just in case anyone else trying to build a TAD 5F1 Champ stumbles across this thread: take the layout's word over the pictures on the website. In my case, red goes to the power tube plate and blue to B+.

Went out hunting for a metal oxide 470 Ohm resistor today, the local shops did not carry any 2W ones, but I've managed to find a 3W 470 Ohm metal oxide resistor. I guess that should do fine.